A touchpad is an input module that allows the user's finger to press or slide on a smooth panel to control the operation of the electronic device. Since the touchpad is very thin, the touchpad is usually applied to a notebook computer, a smart phone, a personal digital assistant (PDA) or any other appropriate electronic device.
As the trend of designing the modern electronic device is toward slimness and light weightiness, the light alloy material has been widely applied to a supporting structure of the touchpad module.
However, if the supporting structure is excessively thin, the mechanical strength of the supporting structure made of the light alloy material is impaired. Moreover, since the durability is reduced, the touchpad module is readily damaged. Moreover, if the surface of the alloy material (e.g., aluminum alloy) is oxidized or subjected to an oxidization treatment, the conductivity of the supporting structure is gradually decreased or even lost. Under this circumstance, the original grounding function of the supporting structure is lost. Since the grounding function is lost, electrostatic charges are gradually accumulated in the touchpad module. In case that an electrostatic discharge (ESD) effect occurs, the circuits or electronic components on the circuit board of the touchpad module are possibly destroyed. Under this circumstance, the touchpad module cannot be normally operated.
For overcoming the drawbacks of the conventional technologies, there is a need of providing a touchpad module with light weightiness and high mechanical structure and having an electrostatic discharge protection function.